900 topic ideas – page 23 of 36.

Measure the flow rate through a narrow tube at constant pressure head and different temperatures. Compare linear, polynomial, and viscosity-based models.

Use smooth plastic, sandpaper, sand, and gravel as interchangeable beds. Investigate how a defined roughness index relates to velocity and discharge.

Vary the slope of a model channel while keeping other conditions constant. Test whether a power model describes the relationship between slope and discharge.

Build channels with different bend radii and film floating tracer particles. Compare velocities along the inner and outer sides of each bend.

Compare straight and meandering channels with the same elevation drop. Model travel time as a function of path length and number of bends.

Compare rectangular, triangular, and semicircular channels with similar cross-sectional areas. Include wetted perimeter and hydraulic radius in the model.

Generate small waves in a long shallow tray and determine their speed using video analysis. Compare a linear model with a square-root model.

Place different numbers of equal-sized stones or rods in the channel. Measure travel time, upstream water level, and discharge.

Simulate aquatic plants using flexible strips or stems. Separately investigate the effects of plant density, height, or flexibility.

Gradually increase the flow until sand or gravel grains of different sizes begin to move. Model critical velocity as a function of grain diameter.

Allow spherical particles or sorted sand grains to settle through a water column. Compare linear, quadratic, and other power models.

Place an equal-sized dye drop into still water at different temperatures. Use image analysis to measure coloured area or colour variance over time.

Compare water containing different proportions of sugar or glycerol in a narrow tube. Investigate how concentration changes the flow rate.

Allow water to leave through a side opening in a container. Vary the water height above the opening and model the horizontal range.

Drain identical containers through openings of different sizes. Also record water level over time and develop a differential-equation model.

Vary the height difference between two water containers while using the same tube. Measure flow rate and drainage time.

Compare defined mixtures of sand, soil, and clay. Record cumulative water infiltration as a function of time.

Investigate how the grain size and layer depth of a sand filter affect flow time and turbidity.

Create a reproducible vortex and film the angular velocity of a marker. Test exponential and power-decay models.

Build water wheels with different blade angles. Measure rotational speed, torque, or electrical output and determine an optimal angle.

Photograph equal-sized ice samples before loading and calculate the visible bubble-area fraction. Compare it with maximum breaking load.

Determine mean bubble diameter, variation, and bubble count using image analysis. Use multiple regression to predict strength.

Freeze identical amounts of water at different rates, for example using different insulation layers. Measure bubble content, transparency, and strength.

Test standardized ice beams at several temperatures below 0 °C. Calculate a comparable breaking stress from failure load and sample geometry.

Produce ice samples with different accurately measured salt concentrations. Investigate strength, density, and fracture behaviour.