Wed: problem questions, independent and dependent variables
Thurs: hypothesis, control, constants, materials
HW: Plan out your procedure
Here is an example (Szymon's experiment)
Problem: What amount of water is best for keeping a cactus alive for four weeks?
IV: amount of water (3 mL, 6 mL, 9 mL)
DV: number of needles dropped from cactus (sign that its unhealthy)
constants: same cactus plant type and size, same location, same time frame for monitoring growth, same growing environment, same temperature water added
control: cactus with no water ( 0mL)
Hypothesis: If I give a small cactus 6 mL of water, then it will be healthy and survive for four weeks without losing too many needles because cacti do not need much water to survive, but too much water can kill them.
1. Gather materials.
2. Set up four cactus plants on a tray on the
kitchen table.
3. Number the plants 1, 2, 3, and 4 with a
sharpie.
4. For plant 1, add no water. This is the control.
5. For plant 2, add 3 mL of water (fill a cup from the sink) using a pipette. Measure the temperature of the water if possible.
6. For plant 3, add 6 mL of water.
7. For plant 4, add 9 mL of water.
8. Let the plants sit on the kitchen table for
4 weeks.
9. After each week, or every Thursday, count
the number of needles that fall from the cactus and take a picture using an iphone.
Label the week as week 1. Check the soil, color of the cactus, as well as count the needles that fall.
10. Repeat step 9 for each of four weeks.
11. After four weeks, determine which amount of water kept the cactus the healthiest and record data.
