diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..372c13e
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+__pycache__/
+
diff --git a/experiment.py b/experiment.py
index 7cb8712..fe867d3 100644
--- a/experiment.py
+++ b/experiment.py
@@ -30,11 +30,56 @@ class Experiment:
 
     experiment: str
     date: str
-    measurements: List[Measurement] = field(default_factory=list)
-    variables: List[Variable] = field(default_factory=list)
+    measurements: dict[str, Measurement] = field(default_factory=dict)
+    variables: dict[str, Variable] = field(default_factory=dict)
 
     def to_json(self):
         # Convert the data class to a dictionary, which can be easily converted to JSON.
         import json
 
         return json.dumps(self, default=lambda o: o.__dict__, sort_keys=True, indent=4)
+
+    def from_json(self, json_str):
+        # Convert a JSON string to a data class.
+        import json
+
+        data = json.loads(json_str)
+        self.__dict__.update(data)
+
+    def add_measurement(self, measurement: Measurement):
+        # Add a measurement to the experiment.
+        if measurement.name in self.measurements:
+            raise ValueError(
+                f"Measurement {measurement.name} already exists in the experiment."
+            )
+        self.measurements[measurement.name] = measurement
+
+    def add_measurements(self, measurements: List[Measurement]):
+        # Add a list of measurements to the experiment.
+        for measurement in measurements:
+            self.add_measurement(measurement)
+
+    def take_measurement(self, source: str, value: float):
+        # Add a measurement to the experiment.
+        if source not in self.measurements:
+            raise ValueError(f"Measurement {source} not found in the experiment.")
+        self.measurements[source].values.append(value)
+
+    def add_variable(self, variable: Variable):
+        # Add a variable to the experiment.
+        if variable.name in self.variables:
+            raise ValueError(
+                f"Variable {variable.name} already exists in the experiment."
+            )
+        self.variables[variable.name] = variable
+
+    def add_variables(self, variables: List[Variable]):
+        # Add a list of variables to the experiment.
+        for variable in variables:
+            self.add_variable(variable)
+
+    def set_variable(self, source: str, value: Any):
+        # Set a variable in the experiment.
+        if source not in self.variables:
+            raise ValueError(f"Variable {source} not found in the experiment.")
+        self.variables[source].value = value
diff --git a/moisture.py b/moisture.py
index d86dd81..b50bb93 100644
--- a/moisture.py
+++ b/moisture.py
@@ -5,15 +5,22 @@ from experiment import Experiment, Measurement, Variable
 
 @dataclass
 class MoistureExperiment(Experiment):
-    def __init__(self, date: str):
-        super().__init__(
-            experiment="Moisture Analysis",
-            date=date,
-            variables=[
-                Variable("cold-soak-time", "hour", (5, 45)),
-                Variable("cold-soak-temp", "degF", (69, 72)),
-                Variable("hot-soak-time", "minute", (5, 20)),
-                Variable("hot-soak-temp", "degF", (180, 200)),
-            ],
-            measurements=[Measurement("moisture-content", "%", (0.06, 0.08))],
-        )
+    def __init__(
+        self,
+        date: str,
+        cold_soak_time: float | None,
+        cold_soak_temp: float | None,
+        hot_soak_time: float | None,
+        hot_soak_temp: float | None,
+    ):
+        super().__init__(experiment="Moisture Analysis", date=date)
+        variables = [
+            Variable("cold-soak-time", "hour", (5, 45), cold_soak_time),
+            Variable("cold-soak-temp", "degF", (69, 72), cold_soak_temp),
+            Variable("hot-soak-time", "minute", (5, 20), hot_soak_time),
+            Variable("hot-soak-temp", "degF", (180, 200), hot_soak_temp),
+        ]
+        self.add_variables(variables)
+
+        measurement = Measurement("moisture-content", "%", (0.06, 0.08))
+        self.add_measurement(measurement)
diff --git a/shelling.py b/shelling.py
index 0ffcd40..c512dea 100644
--- a/shelling.py
+++ b/shelling.py
@@ -5,27 +5,39 @@ from experiment import Experiment, Measurement, Variable
 
 @dataclass
 class ShellingExperiment(Experiment):
-    def __init__(self, date: str):
-        super().__init__(
-            experiment="Shelling Analysis",
-            date=date,
-            variables=[
-                Variable("drum-rpm", "rpm", (30, 40)),
-                Variable("paddle-shaft-rpm", "rpm", (400, 800)),
-                Variable("ring-gap", "in"),
-                Variable("tilt-angle", "deg", (2, 5)),
-                Variable("feed-rate", "lb/hr", (300, 500), 500),
-                Variable("moisture-content", "%", (5, 9)),
-                Variable("pecan-variety", "", None, "desirable"),
-            ],
-            measurements=[
-                Measurement("bin1-weight", "lb"),
-                Measurement("bin2-weight", "lb"),
-                Measurement("bin3-weight", "lb"),
-                Measurement("recirculated-weight", "lb"),
-                Measurement("final-discharge-weight", "lb"),
-                Measurement("bin1-half-yield", "%"),
-                Measurement("bin2-half-yield", "%"),
-                Measurement("bin3-half-yield", "%"),
-            ],
-        )
+    def __init__(
+        self,
+        date: str,
+        drum_rpm: int,
+        paddle_shaft_rpm: int,
+        ring_gap: float,
+        tilt_angle: float,
+        moisture_content: float,
+        feed_rate: int = 500,
+        pecan_variety: str = "desirable",
+    ):
+
+        super().__init__(experiment="Shelling Analysis", date=date)
+
+        variables = [
+            Variable("drum-rpm", "rpm", (30, 40), drum_rpm),
+            Variable("paddle-shaft-rpm", "rpm", (400, 800), paddle_shaft_rpm),
+            Variable("ring-gap", "in", value=ring_gap),
+            Variable("tilt-angle", "deg", (2, 5), tilt_angle),
+            Variable("feed-rate", "lb/hr", (300, 500), feed_rate),
+            Variable("moisture-content", "%", (5, 9), moisture_content),
+            Variable("pecan-variety", "", value=pecan_variety),
+        ]
+        self.add_variables(variables)
+
+        measurements = [
+            Measurement("bin1-weight", "lb"),
+            Measurement("bin2-weight", "lb"),
+            Measurement("bin3-weight", "lb"),
+            Measurement("recirculated-weight", "lb"),
+            Measurement("final-discharge-weight", "lb"),
+            Measurement("bin1-half-yield", "%"),
+            Measurement("bin2-half-yield", "%"),
+            Measurement("bin3-half-yield", "%"),
+        ]
+        self.add_measurements(measurements)